Food allergy is a common and growing problem. It may manifest itself early in life. Infants. In particular those having a so-called atopic constitution, may develop an allergic reaction to various proteins, like those originating from cow's milk, soybeans, egg, peanuts or wheat (gluten). Usually these allergies disappear after several months to years. Later in life new allergies may develop, such as those from dust mites, pollen or other proteins from flowers or constituents from fruit.
People suffering from an allergy may have difficulties in digesting or metabolizing some food constituents, which may lead to undesired side effects and intolerance to such constituent. Lactose-intolerance is a commonly known example thereof, which for that reason is often excluded from hypo-allergic nutritional formulae.
Allergic persons may develop gastrointestinal problems if such a constituent is present in their diet, which may further aggravate the condition of the person.
In allergic persons a strong systemic reaction typically develops after exposure to the allergen. This may result in a variety of symptoms, immediately after exposure, and later, for instance after 1 or 2 days, These reactions are thought to be mediated by the interaction of allergens with Langerhans type cells or dendritic cells, regulatory T cells and with Toll-like receptors (TLR) for example the TLR-4 in cells of the Gut-Associated Lymphoid Tissue (GALT). Through activation of a variety of lymphocytes, eosinophylic cells, mast cells and basophilic cells a specific release of immunoglobulins (Ig), proteases, histamine and cytokines, prostaglandines (PG), leukotrienes, hydroxy eicosatetraenoic acids, interleukins (IL) and other signalling compounds a response is generated to the allergen. It is contemplated that in particular the IgE release by B-cells plays an important role. The constitution of a person to develop an allergic reaction appears to be related to the number of T-helper cells of type 1 and 2 and the amount of regulatory T cells. In particular a low ratio of the number of Th1 to that of Th2 cells, and an abnormal value in the GALT of the ratio of the number of Th2 to that of regulatory cells is thought to reflect an increased risk to developing an allergic reaction. Typically in healthy non-allergic infants such ratio is relatively low briefly after birth, and increases rapidly in the first weeks thereafter.
Symptoms that may be observed as a result of an allergic reaction include a reaction of the skin (irritation, local inflammation), a reaction of the mucus-generating tissue like that in nose, mouth, gut-epithelium, lung and throat (allergic rhinitis, irritation, sneezing, swelling), of the eyes (tears), of the respiratory system (asthma, ventilatory obstruction), of the gastrointestinal tract (diarrhoea, inflammatory response locally or over longer distances of the gut), a systemic reaction (as e.g. manifests itself in increased plasma levels of histamine and lower levels if interferon-gamma) and behavioral problems (irritability, crying periods of babies).
An atopic skin reaction of young infants also frequently leads to an inflammatory response at the child's bottom (diaper rash). Inflammation may also develop in allergic adults, e.g. if they scratch itching areas too many times.
The allergic reactions may further cause pain, itching feelings, and a decrease in performance and body condition. In persons suffering from allergic asthma or allergic bronchitis a shortness of breath is caused. Further it may hinder the sleeping pattern or prevent a normal functioning in life. It may even cause problems that have a severe clinical impact such as causing a shock, in particular an anaphylactic shock.
An anaphylactic shock or another form of an anaphylactic reaction may also occur when insufficiently pure drugs are applied in the treatment of a person having an atopic or allergic constitution, and in particular when the drug is administered via the parenteral route. Examples of such drugs which are known to be at risk for pollution with traces of allergens are antibiotics, local anaesthetics, codeine, drugs prepared from animals or by using exogenous proteins like enzymes such as insulin, adrenocorticotropic hormone, enzymes as such, diagnostic agents like contrast media for MRI or X-ray, vaccines, antitoxins, gamma globulin, interferons, etc. Such anaphylactic shock may further occur when a person, who is at risk for developing such an allergic reaction, is exposed to a venom of plants or animals, for instance that of insects, such as bees, wasps or hornets.
Diagnosis of food allergy is a cumbersome task, especially in young infants. Because classical allergy skin tests are considered to be rather aggressive to babies, other methods are frequently applied such as trial and error experimentation, using conventional diet ingredients, or using less allergic synthetic foods (“hypo-allergic” foods). The potential occurrence of delayed reactions makes interpretation of the results troublesome. Moreover hypo-allergic food may still cause an allergenic reaction. Food legislation defines the criteria to which a hypoallergenic formula must comply. Herein a food is considered hypo-allergenic if its allergenicity is at least 1000 times lower in a challenge test in guinea pigs than the original material from which the ingredients have been prepared.
An example of such a hypo-allergenic food product is Neocate. It comprises amino acids (inter alia tryptophan, threonine, arginine and methionine). The product does not comprise fibers, nor long chain polyunsaturated fatty acids (abbreviated as LCP's).
A need exists for a food product that is non-allergenic, in particular a food for infants, more in particular a food for infants having an atopic constitution.
It would be desirable to provide a non-allergenic food product that provides satisfactory nourishment to the subject, meeting all nutritional demands of such subject, and which product is palatable, and/or convenient to use.
Further, it would be desirable to provide a food that is suitable for use in a diagnostic method for determining an allergy.
It would also be desirable to provide a food product that is capable of ameliorating an allergic response of a subject that is exposed to (small amounts of allergens), e.g. when nourished with a food product that comprises small amounts of allergens or when exposed to drugs that might comprise traces of allergens.
In the gastrointestinal tract of specific groups of infants several conditions prevail, which increase the sensitivity to allergens and favor intolerance to food components. For example infants of young gestational age frequently suffer from an underdeveloped capacity to digest food components, and release abnormal quantities of gastrointestinal hormones and enzymes. This imparts immune function, and in particular the reaction to potential allergens. Coeliac patients suffer from an incapability to completely digest gluten proteins and peptides. Persons suffering from short bowel syndrome and diarrhoea experience increased transit times, which do not allow proper digestion and absorption of the digestive components. Persons suffering from inflammation of the epithelial cells in the gastrointestinal tract such as those suffering from Crohn's disease and other inflammatory bowel diseases, and persons experiencing long-period use of drugs like non-steroidal anti-inflammatory agents, experience a decreased capacity for digestion and absorption of food components.
Also patients, in particular infants, that are exposed to treatment of specific groups of medicaments, such as antibiotics or chemotherapeutics, develop an increased sensitivity to generate an allergic reaction to exposure to a potential allergen. Patients suffering from cystic fibrosis also demonstrate increased levels of larger peptides over a long distance in the gut, a deviating pattern of release of hormones and enzymes that are generated by the gastrointestinal tract and an increased risk for developing allergy.
Despite great efforts to properly feed these specific groups of subjects, especially children, many of them become malnourished. The diseased state of these specific groups also mandates taking all possible precautions to avoid the development of an allergic reaction to the food product that is administered. Therefore a need exists for a food product that properly nourishes specific groups of malnourished persons or diseased persons and that at the same time prevents the development in these patients of an allergic reaction after exposure to potential allergens.